Process for manufacturing 1-[3-cyclopentyl-2(R)-[1(R)-hydroxycarbamoyl)-2-(3,4,4-trimethyl-2,5-dioxo-1-imidazolidinyl)ethyl]propionyl]piperidine

Abstract

A process manufactures of a compound of formula: and unique intermediates.

What is claimed is:  
     
       1. A compound of formula:                    
       wherein R 2  is selected from phenylacyl, diphenylmethyl, p-methoxybenzyl, and benzyl.  
     
     
       2. The compound according to claim  1  which is benzyl (R)-3-cyclopenten-1-enyl-2-hydroxy-propionate. 
     
     
       3. A compound of formula:                    
       wherein R 2  is a hydrolytically cleavable group, R 3  is selected from trifluoromethyl, phenyl and phenyl substituted with nitro or halogen.  
     
     
       4. The compound according to claim  3  which is benzyl (R)-3-cyclopenten-1-enyl-2-(2-nitro-phenylsulphonyloxy)-propionate. 
     
     
       5. A compound of formula:                    
       R 1  is methyl, ethyl, propyl, butyl, pentyl, hexyl or tert-butyl and R 2  is a hydrolytically cleavable group.  
     
     
       6. The compound of claim  5  which is dibenzyl (2R,3R)- and (2S,3R)-2-tert-butoxycarbonyl-3-cyclopent-1-enylmethyl-2-(3,4,4-trimethyl-2,5-dioxo-imidazolidin-1-yl-methyl)-succinate. 
     
     
       7. The compound of claim  5  which is dibenzyl (2R,3R)- and (2S,3R)-2-methoxycarbonyl-3-cyclopent-1-enylmethyl-2-(3,4,4-trimethyl-2,5-dioxo-imidazolidin-1-yl-methyl)-succinate.